Method of making recordings in a recording sheet material

ABSTRACT

A method of making recordings in a recording sheet material is disclosed, wherein the base sheet is applied with a suspension containing finely divided solid particles of color-forming components which essentially comprises (a) leuco dyes and (b) phenolic-aldehyde polymeric condensates and (c) particular types of monomeric substituted phenols the weight ratio of said components (b) and (c) in the range from 90 : 10 to 10 : 90. The resultant product can produce an excellent color-formation when reactive contact among the color-forming components is caused by imparting heat or an ultrasonic vibrating energy.

United States Patent 1191 Higaki et a1.

[ 1 June 11, 1974 1 1 METHOD OF MAKING RECORDINGS IN A RECORDING SHEETMATERIAL [75] Inventors: Taiii l-ligaki, Nishinomiya; Masao Mikumo,Amagasaki, both of Japan [73] Assignee: Kanzaki Paper Manufacturing Co.,

Ltd., Amagasaki, Hyogo, Japan 221 Filed: Dec. 22, 1971 21 Appl. NO.Z210,885

[30 Foreign Application Priority Data Dec, 28, 1970 Japan 45-127821 Dec.29, 1970 Japan 45-126386 [52] US. Cl 346/1, 117/362, 117/368, 117/369,204/l59.21, 346/135 [51] Int. Cl. (101d 9/00, B41m 5/22 [58] Field ofSearch 117/362, 36.8, 36.9; 204/1592]; 346/135, 1

[56] References Cited UNITED STATES PATENTS 2,661,998 12/1953 Pessel346/] 3,162,763 12/1964 Huett et a1 117/368 3,466,184 /1969 Bowler ct all l7/362.2 3,466,185 9/1969 Taylor 117/362 3,539,375 11/1970 Baum117/369 3,576,660 4/1971 Bayless et al. 117/368 3,672,935 6/1972 Milleret al. 117/369 Primary ExaminerWi11iam D. Martin AssistantExaminer-William B. Trenor Attorney, Agent, or Firm-Morgan, Finnegan,Durham & Pine [5 7] ABSTRACT A method of making recordings in arecording sheet material is disclosed, wherein the base sheet is appliedwith a suspension containing finely divided solid particles ofcolor-forming components which essentially comprises (a) leuco dyes and(b) phenolic-aldehyde polymeric condensates and (c) particular types ofmonomeric substituted phenols the weight ratio of said components (b)and (c) in the range from 90 10 to 10 90. The resultant product canproduce an excellent color-formation when reactive contact among thecolor-forming components is caused by imparting heat or an ultrasonicvibrating energy.

5 Claims, 3 Drawing Figures PATEMTEDJUN H 1914 3L816L838 SHEET 2 0F 2FIG. 3

CONTROL A I 1 m EXAMPLE 1| l 1 H] EXAMPLE 2 L i{ J EXAMPLE 5 4H] EXAMPLE4 L 4 H] EXAMPLE 5 L EXAMPLE 6 A4 EXAMPLE 7 L qm CONTROL B L A M] METHODOF MAKING RECORDINGS IN A RECORDING SHEET MATERIAL v forming componentswhich react upon contact to producea visible color, and also to a methodfor making the same.

Mark-forming system utilizing an electron donoracceptor color-formingreaction between basic dyes and monomeric phenols such as heat-sensitiveor pressure-sensitive recording system is well known. In such system,color-forming components comprising basic dyes and monomeric phenolsreact upon reactive contact to produce a visible color with the contactbeing achieved by the use of heat or pressure with or without theexistence of any solvent. The reactive contact herein described meansthat the molecular distance between electron donor and electron acceptoris close enough to each other to cause an electron donoracceptorcolorforming reaction. As an example of such prior recording system,Australian Pat. No. 402,733 (corresponding to US. Pat. No. 3,539,375,issued Nov. 10, I970) discloses a heat-sensitive record materialcomprising a support sheet having crystal violet lactone and a phenolicmaterial solid at the room temperature but capable of liquefying and/orvaporizing at normal thermographic temperature. Attemps have been madeto use suchmonomeric phenols as 4-tertiary-buthylphenol, 4-phenylphenol,a-naphthol, 4,4'-isopropy1idene-diphenol and etc. as phenolic materials.

SUMMARY OF THE INVENTION We have successfully developed an improvedrecording system in which a deep color image is produced on the surfaceof recording sheet through ultrasonic vibrating energy imparted directlyand locally on the sheet surface.

The above mentioned novel recording system has a number of advantagessuch as free from the effect of mechanical inertia, unnecessity of usingtransforming system such as photo-electronic transformation, and viceversa, less defacement of recording equipment, a simple in constractionand high sensitivity, all of which make it possible to apply it tohighspeed printer, facsimile system and etc. I

In the course of establishing the above recording sys-.

The recording sheet according to the invention comprises a base sheethaving solid particles of colorforming components which essentiallycomprises (a) leuco dyes, (b) phenolic-aldehyde polymeric condensatesand (c) monomeric substituted phenols. The

monomeric substituted phenols should have the following general formula:

wherein R is alkyl group having four to 20 carbon atoms, aralkyl group,substituted aralkyl group, phenyl group substituted phenyl group orcycloalkyl group. The weight ratio of phenolic-aldehyde polymericcondensates to monomeric substituted phenols should be within the rangeof from 10 to 10 90.

Among the colorless dyes useful in this invention there are included thecompounds having lactone ring, lactam ring or sultone ring, which arecolorless or light color for themselves but react with acidic materialsupon contact to produce a color. Such compound is generally called asleuco dye, and the following compounds or combination thereof may bementioned as typical leuco dyes:

3,3-bis(p-dimethylaminophenyl)'6- dimethylaminophthalide (crystal violetlactone) 3,3-bis(p-dimethylaminophenyl)4,5,6,7- tetrachlorophthalide9-(p-nitroanilino)-3,6-bis(diethylamino)- 9-xanthenyl-o-benzoic acidlactam (rhodamine B lactam) 3,3-bis(p-dibutylaminophenyl)phthalide(malachite green lactone) 3,3-bis(p-dipropylaminophenyl)phthalide3,3-bis(p-dimethylaminophenyl)-6-aminophthalide3,6-bis(diethylamino)-9-hydroxy-9-xanthenoylbenzensulfonic sultone2-(2',4,6-trimcthylphenylamino)-8-diethylamino- 3,4-benzofluorane2,8-di(n-ethyl-N-ptoluylamino)-fluorane3-diethylamino-o-methylchlorofluorane Typical examples ofphenolic-aldehyde polymeric condensates are p-phenylphenol-formaldehydepolymeric condensates, p-ter-butylphenol-formaldehyde polymericcondensate, p-octylphenol-formaldehyde polymeric Condensate,phenol-formaldehyde polymeric condensate, cresol-formaldehyde polymericcondensate, phenol-acetaldehyde polymeric condensate, and so forth. And,typical examples of monomeric substituted phenols are p-phenylphenol,p-ter-butylphenol, p-octylphenol, p-pentylphenol,2,2-bis(4'-hydroxyphenyl)propane, p-benzyl-phenol, 2,2-bis(4'-hydroxyphenyl)-sec-isobutanep-(4'-chlorophenyl)phenol,cyclohexylphenol and so forth.

The most useful phenolic-aldehyde polymeric condensate in this inventionis a material generally called as novolack which has a free hydroxylgroup and fusability in the absence of cross-linking agent and is waterinsoluble.

Among the phenolic material useful in this invention there are includedthe materials which are solid under the room temperature but liquefiedunder normal thermographic temperatures of 90-200 C. However, it shouldbe noted that the melting point of phenolic materials is not anindispensable factor in the recording system described.

cording sheets'For example, monomeric phenols or thermographictemperatures of 90 200 C.

The above advantages of this invention are selfexplanatory from theexamples described hereinafter and attached drawings.

The recording sheet of this invention may be produced by applying to abase sheet with an aqueous or non-aqueous suspension dispersing thereinfine solid particles of color-forming components. In those cases, it isdesirable that the solid particles of color-forming components aredeposited to the base sheet in a mutually close position thatthe'color-forming components can easily accept a local energy. To complywith this requirements, the base sheet is coated on one side with asuspension system containing solidparticles of colorforming components.Particularly the above process is preferable in manufacturing a recordsheet for the aforementioned recording system. The solvent used in thenon-squeous suspension must be selected from the materials which do notsolve a color-forming components. For the examples of such solventsthere may be mentioned aliphatic hydrocarbons, having 5 12 carbon atomssuch as n-paraffinic hydrocarbon, isoparaffinic hydrocarbon andcycloparaffinic hydrocarbon.

However, usually, aqueous systems are more preferable than non-aqueoussystems from the view points of economy, handling, safety and others.

If necessary, the suspension system may be added thereto with adhesivesor bonding agents such as polyvinyl alcohol, carboxymethyl cellulose,hydroxyethyl cellulose, casein, starch, syntheric latices and etc., inorder that solid particles of color-forming components may be sticked tothe base sheet. Paper or synthetic polymeric materials of sheet form canbe used' forsuch base sheet, but paper is more desirably used sincepaper is more economical and easy to convert. One of the improvements ofmanufacturing method of this invention is control the pH of aqueoussuspension containing color-forming components between 6.0 and l 1.0 byaddition of basic materials or buffers such as sodium hydroxide,potassium hydroxide, ammonia, lower amines and basic salts thereof aswell as urea and thiourea. The control of pH helps to avoid smudge orbackground which often take place during storing or recording process.Another improvement is to put coated and dried sheet to a calendertreatment by means of, for example, supercalender. As the surface of therecording sheet is smoothened by this treatment,

4 this can accept an energy from a stylus uniformly. Also, thistreatment makes the coated layer stronger since the coated layer can bemechanically densified/This may also save the quantity of adhesives insuspension and to simplify the mutual contact of color-formingcomponents. A further improvement is to prepare solid particles ofphenolic materials by uniformly mixing phenolic-aldehyde polymericcondensates and monomeric substituted phenolsunder a melted condition,

and cooling it down to the solidifying point before pulverization.Phenolic solid particles so obtained are more activated in color-formingreaction. The particle size of phenolic materials under this inventionis to be controlled between approximately I and 5 microns. However, thisis not restricted within the above range since this may be voluntarilydetermined according to the required resolution.

, A BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 show a typicalequipment showing the improved recording-system. In FIG. 1, electrodes11 are attached on opposite sides of ceramic piezoelectric substance 12on end of which a stylus 13 is connected: This stylus 13 maybe a pianocode of 700 microns wide by 15 microns thick by 3 milimeters long, andthe edge comes in slight contact with the surface of the running recordsheet 14, say, under a pressure of 1 5 grams. When AC alternatingelectric signal is applied to the ceramic piezoelectric substance 12from an AC source 16, the substance 12 causes a continuous expansion andcontraction making the stylus 13 vibrate according to the frequency ofthe-AC signal, and the vibrating energy is imparted on the surface ofthe recording sheet 14. Although the frequency of vibration andpreferably between from 10 KHz to KHz, this is not restricted within theabove range since this may be determined according to the resonantfrequency of the ceramic electric substance used. Optimum frequency canbe chosen at will according to the size and the shape of the stylus, therecordingspeed, the running speed and the sensitivity of the recordingsheet, the line density of the stylus and so forth. The vibration energycauses a virtual contact among color-forming components, and, as aresult, a visible image is produced on the surface of recording sheetcorresponding to the pattern of applied alternating electric signal. InFIG. 2, the equipment has multi-styli' 15 consisting of a'number ofstylus 15' each of which has a line density of three five linespermilimeter practically capable of producing any type of pattern.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following examplesserve to illustrate further the invention althoughthe invention is notlimited to these examples. The amount of each example shows parts byweight. v Example 1 13.5 parts of p-phenylphenol (m.p. 169 C) was uniitycontroler) and 59.8 parts of water. The particle size of the abovepremixed phenolic materials was approximately 3 5 microns afterball-milling.

Component-E 2-(2',4',6-trimethylphenylamino)- 0.7 part8-diethylamino'3,4-benzofluorane 2.8-di(NethylN-p-toluylamino)- 0.5 partfluorane rhodamine B-anilide 07 part 3-diethylamino-6-methylchrolo- 0.5part fluoranc anionic surfactant 01 part water 15.2 parts The mixturewith above formulation was ground by ball-milling for 2 hours. Theparticle size of the dyes was approximately 3 5 microns afterball-milling.

75.5 parts of resultant Component-A and 17.7 parts of Component-B wereuniformly mixed with 2.7 parts of Dow-620 (styrene-butadiene copolymerlatex, 50 percent of solid content, manufactured by Dow Chemical Co.,USA) and 2.8 parts or percent potassium hydroxide solution. The pH ofthis final suspension was approximately 11.0. Then, this suspension wascoated on one side of a base paper of 50 grams per square meter by theweight of 5 grams per square meter on dry basis. And further, thiscoated sheet was treated by super-calender under nip-pressure of 12.5Kg/cm Example 2, 3, 4, 5,6, 7 Control-A and Control-B Each of theseexamples is similar to Example 1 except. that p-phenylphenol andp-phenylphenolformaldehyde polymeric condensate were used in thecombination with following weight ratio.

The above Control-A and Control- B are similar to Example 1 except thateach of p-phenylphenol (m.p. 169 C) and p-phenylphenol-formaldehydepolymeric condensate (5O 50 mp. 140 C) was'used singly. Namely, when thepreparation of Component-A, each of above materials was used signly asfine particles and mixed with other components in the ball-mill.

The resultant products (i.e., recording sheet) obtained from aboveexamples and controls were experimented using the equipment as shown inFIG. 1.

Each recording sheet obtained through above exam ples and controls wasput to a recording test by means of the equipment as shown in FIG. 1.Namely, ultrasonic energy caused according to alternating electricsignal of 100 V (effective) with frequency of 30 KHZ was locally appliedfrom the stylus to the surface of the recording sheet running at a speedof 50 millimeter per minute. On the other hand, a hot stylus with atemperature of 200 C. scanned over the surface of the recording sheet.The results of the experiment are as shown in the photograph of FIG. 3.In FIG. 3, the dotted line shows the colored image brought about byultrasonic vibrating energy, and two lines of on the right side show thecolored image brought about by the scanning hot stylus.

This photograph of FIG. 3 clearly explains that the independent use ofp-phenylphenol (Control-A) or p-phenyl-phenol-formaldehyde polymericcondensate (Control-B) cannot possibly be applied to the recordingsystem described, and that the recording sheet according to theinvention also provides a remarkable improvement as a no heat-sensitiverecording sheet. Example 8 This example is similar to Example 1 exceptthat 7.5 parts of fine solid particles of p-phenylphenol and 7.5 partsof fine solid particles of p-phenylphenolformaldehyde polymericcondensate were without premixing them, mixed with 0.4 part of anionicsurfactant, 0.5 part of hydroxipropyl cellulose and 59.8 parts of waterin the ball-mill at preparation stage of Component-A.

The resultant recording sheet was experimented in the same way asExample 1, and similar results as in Example 1 were obtained as shown inthe attached photograph of FIG. 3.

Example 9 Component-A 8 parts of p-ter-butylphenol-formaldehydepolymeric condensate (50 50, mp. l28-l31 C) was uniformly mixed with 1.2parts of p-phenylphenol (m. p. 169 C) under melt state. At that time,the weight ratio of both materials is 87: 13. This mixture was thensolidified by cooling and repulverized. And further, this pulverizedmixture was ground by ball-milling for 3 hours with 10 parts of 20percent Nylgum A-85 (Starch phosphate ester, manufactured by W. A.Sholtens Chemishe F abrieken N-.V., I-Iolland) solution and parts ofwater.

Component-B 10 parts of crystal violet lactone and 10 parts of benzoylleucomethylene blue were ground by ball-milling for 2 hours with 10parts of 20 percent Nylgum A- (see above) solution and 70 parts ofwater.

75 parts of resultant Component-A and 15 parts of Component-B wereuniformly mixed with 2.7 parts of Dow-620 (see Example 1). Then, thisfinal suspension was coated on one side of a base paper 50 grams persquare meter by the weight of 5 grams per square meter on dry basis. Andfurther, this coated sheet was treated by super-calender undernip-pressure of 12.5 Kg/cm parts of p-phenylphenol-fonnaldehydepolymeric condensate (50 :50, mp. C) were uniformly mixed under meltcondition. This mixture was then solidified t 7 by cooling andrepulverized. Then, this pulverized mixture was ground by ball-millingfor 2 hours with 100 parts of mineral. spirit and three parts ofcyclolized rubber. Theparticle size of the above premixed phenolicmaterials was approximately 3 5 microns after ballmilling. Component-B 710 parts of crystal violet lactone was ground by ballmilling for 3 hourswith parts of mineral spirit and 0.5 part of cyclolized rubber. Theparticle size of the above dye was approximately 3 microns afterballmilling.

100 parts of resultant Component-A and 20 parts of Component-B wereuniformly mixed. Then, this suspension was coated on oneside of aglassine paper of 40 grams per square meter by the weight of 5 grams persquare meter on dry basis. And further, this coated sheet was treated bysuper-calender under nip-pressure v of 12.5 Kglcm wherein R is alkylgroup having four to 20 carbon atoms, aralkyl group, substituted aralkylgroup, phenyl group, substituted phenyl group or cycloalkyl group, theweight ratio of said phenolicaldehyde polymeric condensates to' saidmonomeric substituted phenols being within the range of 90:10 to 10:90,and subjecting said recording sheet to ultrasonic vibrating energy toproduce a color change in said coating layer corresponding to thedesired recording. I

2. A process as defined in claim 1, wherein said phenolic-aldehydepolymeric condensates and said monomeric substituted phenols areprovided as individual fine solid particles in an aqueous suspension andincluding the steps of coating said suspension on one sidenolic-aldehyde polymeric condensates and monomeric substituted phenolsare suspended in said suspension as premixed fine solid particles.

2. A process as defined in claim 1, wherein said phenolic-aldehydepolymeric condensates and said monomeric substituted phenols areprovided as individual fine solid particles in an aqueous suspension andincluding the steps of coating said suspension on one side of a basesheet to form said recording sheet and drying the coated recordingsheet.
 3. A process as defined in claim 1, in which said coated layerhas a smooth surface.
 4. A process as defined in claim 2, including thestep of maintaining the pH of said suspension within the range of from6.0 to 11.0.
 5. A process as defined in claim 2, wherein saidphenolic-aldehyde polymeric condensates and monomeric substitutedphenols are suspended in said suspension as premixed fine solidparticles.
 90. THE RESULTANT PRODUCT CAN PRODUCE AN EXCELLENTCOLOR-FORMATION WHEN REACTIVE CONTACT AMOUNT THE COLOR-FORMINGCOMPONENTS IS CAUSED BY IMPARTING HEAT OR AN ULTRASONIC VIBRATINGENERGY.